These studies are designed to explore the role of cell surface lectin-carbohydrate interactions, in cellular recognition, cooperation and regulation. Special emphasis is placed on the role of complex carbohydrates and glycoproteins in the regulation of immune response during human pregnancy. A mannose 1-6 dimer of mannose and a more complex glycoprotein have been purified from human pregnancy urine. Both compounds are being extensively characterized for their immunoregulatory properties. A second set of studies is examining a T independent antigen specific model of human antibody production in vitro. These studies are concentrating on 1) cellular requirements, 2) B cell subset diversity, and 3) fine specificity of V region products. A third line of research has explored spontaneous monocyte mediated cytotoxicity with the development of cytotoxic cell lines. Finally, we have used intact and F(ab)2 anti Dr antibodies to disect.